1. Field of the Invention
The present invention is directed to methods of modifying the rheology of thermoplastic resins and in particular to compositions containing thermoplastics and polyolefin containing interpolymers.
2. Description of the Prior Art
Thermoplastics, such as polyolefins are often used in applications such as blown film, cast films, solid sheets, injection molded articles, thermoformed articles, blow molded articles, rotomolded articles, compression molded articles, and functional films. In many processing operations, the throughput rate, melt elasticity, processibility and physical properties such as strength properties, heat seal properties, rheological properties, diffusion properties, and optical properties of the polyolefins do not meet the needs of the end user and/or are slow and/or difficult to process.
As a non-limiting example, the low shear viscosity of many thermoplastics is too low under normal processing conditions and thermoformed articles made from the polyolefin are non-uniform with thin sections that create weak points in the structure of the article.
In another non-limiting example, many thermoplastics can be too elastic under processing conditions resulting in poor processibility and low throughput rates.
As a further non-limiting example, many thermoplastics can be too viscous under processing conditions, also resulting in poor processibility and low throughput rates.
Thus, there is a need in the art for thermoplastic, and in particular polyolefin and elastomer compositions that provide an adequate balance between viscous and elastic properties to provide good processibility while maintaining good physical properties such as strength properties, heat seal properties, and optical properties.